Conventionally, a semiconductor storage device including a NAND-type flash memory and a controller has been produced and marketed. In such a semiconductor storage device, the controller provides an interface between a system and the NAND-type flash memory. In more detail, the controller provides logical address/physical address conversion of the NAND-type flash memory, data caching, an interface and the like. The interface provided by the controller may be a USB interface, a SATA interface or the like.
In such a semiconductor storage device, the NAND-type flash memory and the controller are stacked to form a module. Such modules were first formed actively in the field of semiconductor storage devices including a controller which provides a USB interface. By contrast, in the field of SSDs (Solid State Drives) in which the controller provides a SATA interface, it has been attempted merely recently to stack a NAND-type flash memory and a controller to form a module. A reason for this is that SSDs are expected to replace HDDs (Hard Disc Drives) and thus are required to have a structure including a stack of a plurality of NAND flash memories.
Recently, SSDs including a SATA interface that are directly mountable on a substrate have been produced and marketed. An SSD including a SATA interface has a BGA pattern having an array of a large number of solder balls on a bottom surface of the module. Such an SSD includes a multi-chip package in which a NAND-type flash memories and a controller are stacked.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-35994
However, the conventional SSD including a SATA interface does not include a power supply IC or various types of passive elements. Therefore, the controller needs to be driven by the same external power supply as that for the NAND-type flash memories. This causes problems that a lower level of power supply voltage cannot be used for the controller and that a plurality of power supplies cannot be provided for the NAND-type flash memories. In addition, since the SSD includes the multi-chip package, a test needs to be performed after the SSD is sealed with a resin. This makes it difficult to guarantee a high total yield, which includes the yield of the controller and the yield of the NAND-type flash memories.
The present invention made in light of the above-described problems has an object of providing a semiconductor storage device in which a power supply IC and various types of passive elements are provided in the form of a module, a lower level of power supply voltage can be used for a controller, and a plurality of power supplies can be provided for the controller and NAND flash memories. The present invention also has an object of providing a method for producing such a semiconductor storage device, which can realize a sufficiently high total yield.